1. Field of the Invention
The present invention is directed to tracing a MPLS enabled network and to graphically depicting a network configuration based on the tracing.
2. Brief Description of the Related Art
Internet Protocol (IP) networks may implement Multi-Protocol Label Switching (MPLS) to ensure that packets in a selected flow follow the same route through the network's backbone. In such networks, data packets include routing information that determines the path the data packet follows through the network. To achieve this, MPLS routers attach labels containing forwarding information to data packets before the data packets leave the routers. These MPLS routers are generally located at the periphery of the network and generally perform packet analysis and classification before data packets enter the core of the network. The Label Switch Routers (LSRs) are generally located within the core of the network. These LSRs examine labels assigned to data packets by the MPLS routers and forward the data packets in accordance with the labels. Thus, the LSRs generally are not required to look up information in, for example, routing tables and generally are not required to compute path forwarding information for each data packet. Once a data packet traverses the network and reaches its destination, the edge router at the destination removes the label.
A fundamental concept in successful operation of Multi-Protocol Label Switching (MPLS) networks is that two Label Switch Routers (LSRs) must agree on the meaning of labels used to forward traffic between and through them. This common understanding is achieved by a set of procedures, called Label Distribution Protocol (LDP), by which one LSR informs the other of the label bindings it has made. LDP is a set of procedures and messages by which LSRs establish Label Switched Paths (LSPs) through the network by mapping the network-layer routing information directly to the data-link layer switched paths.
Conventional approaches for tracing a network generally traverse a network by checking each router in sequence, as each path is traversed. Nodes that are common to multiple paths are typically revisited each time they are encountered when tracing paths. The conventional approaches are typically very time consuming, especially as path complexity between endpoints (e.g., source and destination routers) increases. For example, these conventional approaches can require in excess of 45 minutes.
In addition, conventional approaches for conveying network configurations of a network based on result of the trace are typically textual or depicted graphically as a tree diagram. These techniques for conveying network configurations can be inaccurate and/or inefficient. For example, textual description of network configurations can be difficult to read and understand and tree diagrams may repetitively depict nodes that are used in multiple paths.
A new approach that traces routing paths in an IP MPLS network, which is efficient in time and cost is desirable. In addition, an intuitive and accurate portrayal of trace results using information obtained from the traces performed is also desired.